The "Cornerstone Building system" was born in Oxford, a little North Canterbury town with a population of 1800, at the foothills of the Southern Alps, in the South Island of New Zealand. Mary Ginn, one of three inventors involved in the original idea, and the driving force, has bought that idea through to fruition. Mary remains committed to housing people in the best possible energy efficient, sustainable buildings. The focus on homeowners comfort, security and quality without the extra cost usually associated with what we should be able to expect in a home.

The "idea" was the easy part of the equation. Firstly in 1994 they applied to patent the system and next the first customer willing to go through with this experiment. In 1995, the Christchurch City Council sent them off to the Building Research Association New Zealand (BRANZ) to have the product tested before consenting the plan and going into the market. Rigorous testing to see how it would stand up in earthquake and high winds and a fire test was carried out and all tests exceeded their expectations. It took many years of developing and perfecting the system with all the tooling required, (aiming to "keep it simple"). The astronomical costs involved in patenting and marketing a product, was a long hard process on an extremely tight budget. "What budget?" Actually there was no budget just shear determination, passion and purpose to offer something Mary totally believes in.

Mary's background in the industry was very much hands on when women were not seen on the building site. Actually as a teenager, girls were not allowed to go into these areas of employment. Her experience spread across the range of trades and professions from project management, building, interior decorating & stopping, architectural design, quantity surveying, costing, property development and sales. Her practical training in Building and Architectural design started with her own family home in the early 1980's Mary and her husband were the typical Kiwi "Do it yourselfer's" (DYI), then designing for the various builders and customers in Oxford. Here the North Westly winds usually tested the buildings, extremes of temperature prevailed, high electricity bills and her enquiring mind as to why we were building with the 4 x 2 timber method. Mary, her husband and friends had set up a in Oxford, in building development company's with Mary later spending a few years studying at Oxford Area school as an adult student. She travelled into Christchurch polytechnic to study Architecture which she had already been achieving practically, in the early 1990's.

Mary's desire to find a better way to build, generate and minimize energy use along with sustainable practices, set the stage for her to set about trying to improve the way we build in New Zealand. A mix of an open mind, meeting of the right people, seeing what products were used internationally and the fact that other countries build for longevity compared to our New Zealand short term, throw away approach to standard construction methods assisted that process.

The first "Cornerstone house" was constructed in 1995 in Christchurch, then after a few more houses to perfect the system, now there are homes, schools, motels etc all over the country which have very happy clients, some building for a second time with the "Cornerstone Building system".

In the early years it was difficult to convince people that a product 90% Polystyrene and 10% reinforce concrete, was a good way to build their biggest investment in. Of course the product (Polystyrene) has been proved to have excellent uses in construction in many ways. It does not rot or break down and has excellent insulation properties and there is so much research available now to support polystyrene as a superior product.